Composite cementitious discrete-element feedstock

ABSTRACT

A composite cementitious feedstock comprises discrete elements. Each discrete element includes mineral rock agglutinates having irregular surface regions and cavities. Super absorbent polymer (SAP) particles and cement particles are disposed on the irregular surface regions and in the cavities. A binder coheres the agglutinates, SAP particles, and cement particles.

FIELD OF THE INVENTION

The invention relates generally to cementitious materials, and moreparticularly to a composite cementitious material in the form of adiscrete element suitable for use as feedstock in mortar and concreteconstruction systems.

BACKGROUND OF THE INVENTION

Concrete materials used in construction applications typically includemineral-based cement mixed with rock aggregate and sand. For example,the well-known and widely-used Portland cement is produced by firing amixture of finely ground clay and limestone. The rock aggregates andsand that are added to the cement to make concrete can be pre-mixed withthe cement in a granular material form and packaged, or can be addedseparately as an ingredient when mixing the cement powder with water inorder to create a concrete slurry. This resulting concrete slurry canthen be transferred into a mold, formwork or directly applied by hand,or in a “spray on” type of operation. The addition of water initiates ahydration process that causes an exothermic chemical reaction thatultimately results in the curing and hardening of the concrete materialinto a synthetic rock.

When cement is mixed with a fine aggregate such as sand, then it iscalled a mortar. When fine sand or other fine rock material is mixedwith cement and used to fill gaps between tiles or in industrialapplications such as oil wells, then it is called a grout. When cementis mixed with fine and coarse aggregates, then it is called a concrete,which typically has a higher strength and lower cost than mortar orgrout, due to less cement used and the high strength of the includedrock aggregates. A variety of other cements have been developed, such ascalcium aluminate cements, pozzolanic cements, lime concrete/mortar andexpansive cements, but the quantities of these other cements usedworldwide are small compared with composite cements based on Portlandcement. Composite cements (also known as blended cements) containPortland cement and other reactive inorganic material that contributesignificantly to the hydration process. The most common examples of suchmineral additives are fly ash, microsilica, metakaolin, volcanic glass,blast furnace slag, and limestone. The additives can significantlyimprove concrete performance in terms of improved strength ordurability. In addition, admixtures such as super plasticizers,accelerators, water reducers/retarders, and other process performancerelated advantageous materials can be used. Reinforcement materials suchas chopped glass fibers, carbon fibers, KEVLAR fibers, polymer strands,or steel reinforcing bar can also, or alternatively, be added to improvematerial strength.

Currently, existing concrete automated additive construction systems(also known as three-dimensional (3D) printing systems) are fed with awet Portland cement concrete slurry that is pre-mixed and then pumpedthrough a hose to a print head nozzle where it is extruded to formadditive layers successively that results in a monolithic structureafter the concrete cures. The concrete slurry must be mixed andmaintained at the correct viscosity in order to prevent slumping orcrumbling at the print head application location. The exothermicconcrete slurry mixture can suffer from thermal runaway issues making ithard to control the concrete application and curing properties. Cleanupof the mixing system, pump, hoses and extrusion print head is difficultand time consuming since it must be manually flushed out with waterbefore the concrete slurry cures and hardens to clog the pumping system,hoses and print head. The existing concrete 3D printing systems cannotbe turned on and off as needed without extensive hose and print headcleaning operations. Complex procedures are required to control thematerial mix, rheology, and consistency. If the mix is not correct, thenan entire large scale structure could be compromised due to insufficientstructural strength, cracking, slumping or creep caused by poorly mixedand/or poorly applied concrete slurry.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide acementitious product that improves the automated additive constructionthree-dimensional (3D) concrete printing process.

Another object of the present invention is to provide a cementitiousproduct that improves the end-product structure constructed by athree-dimensional (3D) concrete printing process.

Still another object of the present invention is to provide acementitious product that simplifies the handling thereof prior to andduring its use for concrete construction.

Other objects and advantages of the present invention will become moreobvious hereinafter in the specification and drawings.

In accordance with the present invention, a composite cementitiousfeedstock comprises a plurality of discrete elements. Each discreteelement includes mineral rock agglutinates having irregular surfaceregions and cavities originating at their irregular surface regions.Super absorbent polymer (SAP) particles are disposed on the irregularsurface regions and in the cavities. Cement particles are disposed onthe irregular surface regions and in the cavities. A binder is providedto cohere the agglutinates, SAP particles, and cement particles.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention willbecome apparent upon reference to the following description of thepreferred embodiments and to the drawings, wherein correspondingreference characters indicate corresponding parts throughout the severalviews of the drawings and wherein:

FIG. 1 is a schematic view of an agglutinate-based constituent of acomposite cementitious discrete element in accordance with an embodimentof the present invention;

FIG. 2 is a schematic view of composite cementitious discrete elementusing a plurality of the agglutinate-based constituent illustrated inFIG. 1 in accordance with the present invention;

FIG. 3 is a schematic view of a composite cementitious discrete elementwhose binder is an encapsulating outer layer in accordance with anembodiment of the present invention;

FIG. 4 is a schematic view of a composite cementitious discrete elementwhose binder is dispersed throughout the discrete element in accordancewith another embodiment of the present invention;

FIG. 5 is a schematic view of a composite cementitious discrete elementwhose binder is generated by electrostatic charges in accordance withanother embodiment of the present invention;

FIG. 6 is a schematic view of a composite cementitious discrete elementincluding SAP-coated sand particles in accordance with anotherembodiment of the present invention;

FIG. 7 is a schematic view of a composite cementitious discrete elementthat includes reinforcement fibers in accordance with another embodimentof the present invention;

FIG. 8 is a schematic view of a composite cementitious discrete elementthat includes electromagnetic energy absorbing powder in accordance withanother embodiment of the present invention; and

FIG. 9 is a schematic view of a composite cementitious discrete elementthat includes nanophase iron in accordance with another embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a composite cementitious discrete element thatcan be used in the making of concrete. Briefly, to make concrete, aplurality of the present invention's discrete elements are activated bybeing mixed with water and/or electromagnetic energy heating and/orelectrical resistance heating depending on how the discrete elements areconfigured. As used herein, activation of the discrete elementsinitiates the conversion of the composite cementitious material to a wetconcrete. However, in all of embodiments of the present invention, thediscrete elements can be conveyed in a dry state as feedstock to adispensing apparatus (e.g., a 3D printer, concrete boom etc.) or into astructural form (e.g., bed, floor, wall, etc.) just prior to activationby water and/or electromagnetic energy and/or electric resistanceheating. In this way, the problems associated with mixing, transporting,and dispensing wet concrete slurries are eliminated.

In general, each discrete element in accordance with the presentinvention has agglutinate-based constituents cohered by a binder thatdissolves or dissipates at time of activation. A variety of non-limitingembodiments of such agglutinate-based constituents will be describedherein. While the various embodiments described herein may differ by asingle feature, it is to be understood that the features of two or moreof the described embodiments could be combined to define anotherembodiment without departing from the scope of the present invention.

Referring now to the drawings and more particularly to FIG. 1 , a basicembodiment of an agglutinate-based constituent for use in the presentinvention is shown and is referenced generally by numeral 10. The threebasic features included in constituent 10 are a mineral rock agglutinate12, a plurality of super absorbent polymer (SAP) particles 14, and aplurality of cement particles 16. Each of these features of constituent10 will be described further below.

Mineral rock agglutinate 12 can be a naturally-occurring or man-mademineral rock agglutinate without departing from the scope of the presentinvention. While naturally-occurring mineral rock agglutinates aregenerally found on the Moon but not on Earth, man-made simulants oflunar agglutinates are known in the art. For example, a man-madeagglutinate could be made by plasma melting basalt rock and dropping themolten basalt rock into a water bath causing it to rapidly cool toambient temperature. Other methods of melting rock include the use oflasers or solar concentrators. Accordingly, it is to be understood thata variety of rock melting processes can be used to form agglutinate-likeglassy particles on Earth. Additional suitable mineral rock materialsthat can be used to make lunar-simulating agglutinates include, but arenot limited to, olivine, pyroxene, and plagioclase feldspar (i.e.,anorthosite). For purposes of the present invention, sizes ofagglutinate 12 typically are in the range of 250 microns to 1000microns.

Regardless of the type of mineral rock(s) used for agglutinate 12 or thesizes thereof, all such agglutinates are defined by a highly irregularsurface 120. As would be understood in the art, the term “irregularsurface” as it applies to lunar-simulated agglutinates refers to avariety of irregular surface features that can include sharp and smoothsurface undulations, pocks, pores or cavities, dendritic-like tentacles,etc., and that such surface features are unique to every agglutinate. Tomaintain clarity of illustration, just a few surface featuresoriginating at surface 120 are shown and referenced in FIG. 1 . Morespecifically, irregular surface 120 includes undulating surface regions122, pocks 124, pores or cavities 126, and dendritic-like tentacles 128.

Disposed on the surface features of surface 120 and in cavities 126 areSAP particles 14 and cement particles 16. It is to be understood thatthe number and arrangement of particles 14 and 16 illustrated in FIG. 1are merely for purposes of illustration. In actuality, the number of SAPparticles 14 and cement particles 16 will be far greater than thatillustrated and relative sizes will vary. In all cases, locations ofparticles 14 and 16 on surface 120 and in cavities 126 are random. Forclarity of illustration, only a few of SAP particles 14 and cementparticles 16 are indicated with reference numerals. For purposes of thepresent invention, sizes of SAP particles 14 range from 1 micron to 120microns (i.e., as defined by the American Society for Testing andMaterials (ASTM) E11 sieve #120) and cement particles 16 typically rangefrom sub-micron to 100 microns.

SAP particles 14 can be any of a variety of super absorbing polymershaving a water absorption capacity that greatly exceeds their own mass.Some hydrogels can absorb up to thousands times more water than theirdry weight. By way of non-limiting examples, typical super absorbingpolymers for use in the present invention could include the followingknown and/or commercially-available SAPs:

hydrophilic polymers that can be developed to be biodegradable andbiocompatible, and can be synthetized from a variety of synthetic (e.g.,poly(vinyl alcohol) (PVA), poly(ethylene glycol) (PEG) andpoly(propylene fumarate) (PPF)) or natural (e.g., alginate, gelatine,hyaluronic acid, fibrin and chitosan) resources;poly (meth) acrylates of alkaline salts, starches grafted with a (meth)acrylic polymer, hydrolysed starches grafted with a (meth) acrylicpolymer; polymers based on starch, gum, and cellulose derivative, andmixtures thereof;polymers resulting from the polymerization with partial crosslinking ofhydrosoluble ethylenically unsaturated monomers, such as acrylic ormethacrylic polymers (resulting especially from the polymerization ofacrylic and/or methacrylic acid and/or of acrylate and/or methacrylatemonomers) or vinyl, in particular crosslinked and neutralized poly(meth) acrylates, especially in the form of a gel, and the alkalinesalts such as the sodium or potassium salts of these polymers;starches grafted with polyacrylates;acrylamide/acrylic acid copolymers, typically in the form of salts,especially of alkaline salts and in particular of sodium or potassiumsalts;acrylamide/acrylic acid grafted starches, typically in the form ofsalts, especially of alkaline salts and in particular of sodium orpotassium salts;the salts, in particular the alkaline salts and in particular the sodiumor potassium salts, of carboxymethylcellulose;the salts, in particular the alkaline salts and in particular the sodiumor potassium salts, of crosslinked polyaspartic acids; andthe salts, in particular the alkaline salts and in particular the sodiumor potassium salts, of crosslinked polyglutamic acids, and mixturesthereof.

Cement particles 16 can be any of variety of known cements. By way ofnon-limiting examples, typical cements for use in the present inventioncould include the following:

-   Portland cement and Portland cement blends;-   Pozzolan-lime cements;-   Silica fume cements;-   Calcium aluminate cements;-   Gypsum cements;-   Hydroxyapatite (phosphate mineral) cements;-   Magnesia-ammonium phosphate cements;-   Geopolymer cements;-   Magnesium oxide or basalt-based cements;-   Cements made by made by burning septaria;-   Rosendale natural cements;-   Blast slag-lime cements;-   Supersulfated cements;-   Calcium sulfoaluminate cements; and-   Cements produced by burning argillaceous limestones at moderate    temperatures.

Referring now to FIG. 2 , a composite cementitious discrete element inaccordance with an embodiment of the present invention is shown and isreferenced generally by numeral 20. Discrete element 20 includes abinder 30 for cohering a plurality of the above-described constituents10 (i.e., agglutinate 12 with particles 14 and 16 thereon) andadditional SAP particles 14 and cement particles 16 dispersed amongstconstituents 10 and throughout discrete element 20. As will be explainedfurther below, binder 30 can be realized using a binder material orelectrostatic charges without departing from the scope of the presentinvention. However, in all cases, binder 30 dissolves or dissipates whendiscrete element 20 is activated to initiate its conversion to a wetconcrete.

When discrete element 20 is to be activated by water, binder 30 is abinder material that is water soluble. For example, water-soluble bindermaterials include synthetic/semisynthetic water-soluble polymers such aspolyvinylpyrrolidone, poly vinylsulfonate, polyacrylic acid,polymethacrylic acid, poly 2-acrylamido-2-methylpropanesulfonic acid,polyacrylamide, polystyrenesulfonate, partially hydrolyzedpolyvinylacetate, polyethylene glycol, polyvinyl alcohols, copolymersthereof, and mixtures thereof. Other examples are methyl cellulose,hydroxy propyl methyl cellulose, hydroxy propyl cellulose, sodiumcarboxy methyl cellulose and natural binders such as gelatin, starch andcellulose. When binder 30 is a water-soluble material, discrete element20 contains 1-30 weight percent of binder 30 and 70-99 weight percent ofconstituents 10 and the additional SAP particles 14 and cement particles16 dispersed amongst constituents 10 and throughout the discreteelement.

The material used for binder 30 can be nonflammable for applicationsrequiring this feature. In such cases, a sufficient amount of a flameretardant could be added to binder 30 to make it nonflammable. A varietyof flame retarding materials is well known in the art.

A material-based binder 30 can also be realized as an encapsulatingouter layer 32 of discrete element 20 as illustrated in FIG. 3 .However, the present invention is not so limited as a material-basedbinder 30 could also be realized as a dispersant 34 throughout all ofdiscrete element 20 as illustrated in FIG. 4 . Still further, amaterial-based binder 30 could be realized as a combination of adispersant 34 of the discrete element and an encapsulating outer layer32 of the discrete element without departing from the scope of thepresent invention.

As mentioned above, binder 30 can also be realized by electrostaticcharges between constituents 10 and the additional SAP particles 14 andcement particles 16 as illustrated in FIG. 5 where the attractive forces36 developed between “+” and “−” electrostatic charges in discreteelement 20 are shown. For clarity of illustration, only a few of suchattractive forces are illustrated. Furthermore and as would beunderstood in the art, attractive forces 36 would retain the parts ofdiscrete element 20 in a close-pack relationship. That is, thespaced-apart relationships of the parts of discrete element 20 shown inFIG. 5 are merely for purposes of illustration. The electrostaticcharges can be introduced during fabrication of the discrete element viathe process known as turbocharging, i.e., processing through pneumaticconveying and cyclone devices or by exposure to an electrically chargedfield. To activate discrete element 20 shown in FIG. 5 , water is addedwhereby the electrostatic charge bleeds off as the humidity createselectrical conduction paths in which electrons can travel and neutralizethe existing charges. The loss of opposite charges on the particlescauses a loss of electrostatic cohesion so the particles are able toseparate and mix freely to activate the cement mixture.

Another embodiment of a discrete element 20 is illustrated in FIG. 6where particles of mineral sand 18 are dispersed throughout the discreteelement. More specifically, sand particles 18 are partially or fullycoated with SAP particles 14. The SAP-coated sand particles can bedispersed throughout the discrete element to include on the surface ofagglutinates and in the cavities thereof. For purposes of the presentinvention, sizes of sand particles 18 typically are in the range of from53 microns (i.e., as defined by ASTM sieve #270) to 150 microns (i.e.,as defined by ASTM sieve #100) average diameter. The coated sandparticles are efficient carriers of the SAP so that the SAP can beevenly distributed and mixed within the dry cement composite mixture.When water is added to begin activation, the SAP absorbs the water tothereby form an adhesive layer of water around the sand particles due toits hydrophilic property aided by the cohesion of the water moleculesand the corresponding surface tension of the water film that formsaround each sand particle. The result is the formation of a hydrogelsurrounding the distributed sand. This efficient distribution of waterin the cement mixture prevents self-dessication, which leads to a moreconsistent hydration process in the cement hardening chemical reactionresulting in improved mechanical properties. The microscopic voids leftbehind after hydration make the concrete more resistant to freeze andthaw cycles in harsh climates. In addition, the wet SAP creates asignificant advantage in the rheology of the wet slurry as it thickensso that slumping is reduced and viscosity is increased, which isadvantageous in 3D printing processes. The SAP also creates a reductionin shrinkage or drying out of the concrete. Self-dessicated concretecauses cracking of the structure during curing and needs to be avoidedfor quality control.

Discrete elements in accordance with the present invention could alsoinclude one or more of the features illustrated in FIGS. 7-9 . Forexample and as shown in FIG. 7 , each discrete element could includereinforcement fibers 40 dispersed therein that will add strength to theultimate structure (not shown) once the discrete elements have beenactivated and ultimately unified/cured. Fibers 40 can be chopped fibersor nano fibers, and can include, for example, glass fibers, hydrocarbonpolymer fibers, metallic fibers, carbon fibers, KEVLAR fibers,cellulose, and mixtures thereof.

When discrete elements of the present invention are to be activatedsolely or additionally by heat, the discrete elements can include powderparticles 50 dispersed therein as illustrated in FIG. 8 . Powderparticles 50 can be any of a variety of commercially-availableelectromagnetic energy absorbing materials/powders. In general, powderparticles 50 are selected from a class of materials that absorbelectromagnetic energy in a range of 300 MHz to 300 GHz.

Still another embodiment of a discrete element of the present inventionis illustrated in FIG. 9 where some or all of constituents 10 includenanophase iron particles 60 coupled thereto. Nanophase iron is aneffective absorber of electromagnetic energy in a range of 300 MHz to300 GHz (microwaves) and, therefore, can serve as an efficient susceptorto heat the material mixture thereby hastening dissolution of thediscrete element's binder and cause a more rapid concrete activation. Inaddition, a concrete structure containing embedded nanophase ironparticles throughout could be post-processed with electromagnetic energyheating to cause sintering of the mineral rock particles to furtherenhance the strength of a structure.

The advantages of the present invention are numerous. The presentinvention's novel discrete element feedstock can be introduced intoconstruction systems with water being added in a subsequent step tocreate a hydrated concrete material. The present invention can be usedin the construction of structures that are typically large in scale(e.g., meters to tens of meters or larger, in all linear dimensions).The discrete elements of composite cementitious feedstock can beproduced/used in the form of, for example, approximately cylindrical,ellipsoid, spherical shaped pellets/nodules, or combinations thereof.The sizes of the discrete elements can vary depending on theapplication, and could range from 1 millimeter to 10 centimeters or morein diameter and/or length.

This new type of discrete element feedstock can be used to createself-supporting structures for civil engineering infrastructure, suchas, but not limited to, buildings, homes, industrial facilities,bridges, antenna towers, liquid and gas storage tanks, flood barriers,retaining walls, foundations, footers, form work, parking lots, roads,driveways and many other useful structures. Some examples ofapplications could include disaster mitigation (eg. rapidly constructflood barriers before the flood), military combat (build in-situ blastbarriers, barricades and shelters) and affordable custom housing for theglobal population. The present invention's discrete element feedstockcan be emplaced while dry, or as a mixture that is activated by waterjust in time at an extrusion print head nozzle. Each discrete element'sbinder initially holds the discrete element together for transportationto a construction site, and conveying to the print head where waterand/or additives can be added in a real-time emplacement step in orderto dissolve the binder while also initiating concrete hydration and theconcrete material's curing process.

The discrete element feedstock enables an effective way of conveyingconcrete construction material in a non-hazardous fashion since thetypically dusty cement and fine sand aggregate is completely containedin the discrete element. It is well known that cementitious dust is ahealth hazard to construction personnel and can also be detrimentalduring the construction process if there is wind or other air currentswhich will blow the cement dust away from its intended site of use. Byusing discrete element pellets and/or nodules, efficient and potentiallyautomated conveying techniques can be used such as pneumatic conveying,motor driven flexible augers, bucket chains, conveyor belts, ballistictransfer or other means which will enhance construction methods.

Large amounts of concrete are required for construction projects incivil engineering applications. Mixing the concrete slurry on site isdifficult and costly, so concrete is often mixed at a centralized plantlocation and specialized concrete transportation trucks deliver thepre-mixed concrete in a slurry form to the construction site in largebatches. The problem with this approach is that the concrete slurry hasalready been mixed with water thereby commencing the hydration processbefore the concrete is emplaced. Accordingly, to avoid curing, the wetconcrete reaction must be retarded with additives and in order topromote even mixing and segregation of the granular materials of varyingsizes (i.e., sand, aggregates), it must be agitated or tumbled inexpensive and logistically difficult concrete trucks mounted with largerotating containment vessels. In contrast, by preparing the presentinvention's discrete element feedstock at a factory site andtransporting it to a construction site, the expensive logistics ofcurrent slurry concrete transportation and emplacement methods can bereduced substantially. The discrete element feedstock can be deliveredand dry stored in bags, or placed in a drier vessel to avoid atmospherichumidity absorption at the construction site for in-situ utilization ondemand. Since the discrete element feedstock is pre-mixed in the exactproportions needed, the segregation of materials is avoided and qualitycontrol of the mix is maintained throughout transportation, deployment,and application/usage at the construction site.

Although the invention has been described relative to a specificembodiment thereof, there are numerous variations and modifications thatwill be readily apparent to those skilled in the art in light of theabove teachings. It is therefore to be understood that, within the scopeof the appended claims, the invention may be practiced other than asspecifically described.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A composite cementitious feedstock comprising aplurality of discrete elements, wherein each discrete element from saidplurality of discrete elements includes mineral rock agglutinates, eachof said agglutinates having irregular surface regions and cavitiesoriginating at said irregular surface regions, super absorbent polymer(SAP) particles, wherein at least a portion of said SAP particles aredisposed on said irregular surface regions and in said cavities, cementparticles, wherein at least a portion of said cement particles aredisposed on said irregular surface regions and in said cavities, and abinder for cohering said agglutinates, said SAP particles, and saidcement particles.
 2. A composite cementitious feedstock as in claim 1,wherein each said discrete element further includes mineral sandparticles, said mineral sand particles being at least partially coatedwith said SAP particles.
 3. A composite cementitious feedstock as inclaim 1, wherein said binder comprises a water soluble material.
 4. Acomposite cementitious feedstock as in claim 1, wherein said binder isnonflammable.
 5. A composite cementitious feedstock as in claim 1,wherein said binder comprises an encapsulating outer layer of saiddiscrete element.
 6. A composite cementitious feedstock as in claim 1,wherein said binder is dispersed throughout said discrete element.
 7. Acomposite cementitious feedstock as in claim 1, wherein said bindercomprises electrostatic charges within said discrete element forgenerating attractive forces between said mineral rock agglutinates,said SAP particles, and said cement particles.
 8. A compositecementitious feedstock as in claim 1, further comprising reinforcementfibers dispersed throughout said discrete element.
 9. A compositecementitious feedstock as in claim 1, further comprising a powderdispersed throughout said discrete element for absorbing electromagneticenergy in a range of 300 MHz to 300 GHz.
 10. A composite cementitiousfeedstock as in claim 1, wherein at least a portion of said mineral rockagglutinates include nanophase iron coupled thereto.
 11. A compositecementitious feedstock comprising a plurality of discrete elements,wherein each discrete element from said plurality of discrete elementsincludes mineral rock agglutinates having sizes ranging from 250 micronsto 1000 microns, each of said agglutinates having irregular surfaceregions and cavities originating at said irregular surface regions,super absorbent polymer (SAP) particles having sizes ranging from 1micron to 120 microns, wherein at least a portion of said SAP particlesare disposed on said irregular surface regions and in said cavities,cement particles having sizes ranging from sub-micron to 100 microns,wherein at least a portion of said cement particles are disposed on saidirregular surface regions and in said cavities, and a water solublebinder for uniting said agglutinates, said SAP particles, and saidcement particles in said discrete element.
 12. A composite cementitiousfeedstock as in claim 11, wherein each said discrete element furtherincludes mineral sand particles having sizes ranging from 53 microns to150 microns, said mineral sand particles being at least partially coatedwith said SAP particles.
 13. A composite cementitious feedstock as inclaim 11, wherein said water soluble binder is nonflammable.
 14. Acomposite cementitious feedstock as in claim 11, wherein said watersoluble binder comprises an encapsulating outer layer of said discreteelement.
 15. A composite cementitious feedstock as in claim 11, whereinsaid water-soluble binder is dispersed throughout said discrete element.16. A composite cementitious feedstock as in claim 11, furthercomprising reinforcement fibers dispersed throughout said discreteelement.
 17. A composite cementitious feedstock as in claim 11, furthercomprising a powder dispersed throughout said discrete element forabsorbing electromagnetic energy in a range of 300 MHz to 300 GHz.
 18. Acomposite cementitious feedstock as in claim 11, wherein at least aportion of said mineral rock agglutinates include nanophase iron coupledthereto.
 19. A composite cementitious feedstock as in claim 11, whereinsaid water soluble binder comprises 1-30 weight percent of said discreteelement.
 20. A composite cementitious feedstock comprising a pluralityof discrete elements, wherein each discrete element from said pluralityof discrete elements includes mineral rock agglutinates having sizesranging from 250 microns to 1000 microns, each of said agglutinateshaving irregular surface regions and cavities originating at saidirregular surface regions, super absorbent polymer (SAP) particleshaving sizes ranging from 1 micron to 120 microns, wherein at least aportion of said SAP particles are disposed on said irregular surfaceregions and in said cavities, cement particles having sizes ranging fromsub-micron to 100 microns, wherein at least a portion of said cementparticles are disposed on said irregular surface regions and in saidcavities, and a water soluble binder for uniting said agglutinates, saidSAP particles, and said cement particles in said discrete element, saidwater soluble binder comprising at least one of a dispersant dispersedthroughout said discrete element and an encapsulating outer layer ofsaid discrete element.
 21. A composite cementitious feedstock as inclaim 20, wherein each said discrete element further includes mineralsand particles having sizes ranging from 53 microns to 150 microns, saidmineral sand particles being at least partially coated with said SAPparticles.
 22. A composite cementitious feedstock as in claim 20,wherein said water soluble binder is nonflammable.
 23. A compositecementitious feedstock as in claim 20, further comprising reinforcementfibers dispersed throughout said discrete element.
 24. A compositecementitious feedstock as in claim 20, further comprising a powderdispersed throughout said discrete element for absorbing electromagneticenergy in a range of 300 MHz to 300 GHz.
 25. A composite cementitiousfeedstock as in claim 20, wherein at least a portion of said mineralrock agglutinates include nanophase iron coupled thereto.
 26. Acomposite cementitious feedstock as in claim 20, wherein said watersoluble binder comprises 1-30 weight percent of said discrete element.